Currently, a superframe structure defined in the China National Sensor Network Standard includes a beacon, an active period, and an inactive period, where the beacon is used to send synchronization information and superframe information; the active period is used to transmit data; and in the inactive period, a network device enters a sleep state, and does not transmit any data.
As a wireless sensor network technology develops, applications of a personal area network are diversified constantly. In an application scenario of the personal area network, such as an application scenario of wireless meter reading, because unpredictable complicated channel fading exists in time and space, a data communication process is seriously affected. Therefore, before communication is performed on the personal area network, it is particularly important for a coordinator in the personal area network to select a channel with relatively good quality for communication of the personal area network by scanning and detecting channels.
In the prior art, when a personal area network is built, a coordinator in the personal area network selects a channel with a minimum energy level from to-be-scanned channels that are specified by an upper layer, and broadcasts information about the channel in the personal area network by using a beacon, so that all nodes in the personal area network perform communication by using the channel, and the nodes in the personal area network keep performing communication by using the channel.
However, in the foregoing method of selecting a channel by the coordinator, on one hand, scan, detection, and evaluation can only be performed on a channel once, only quality of the channel in a short time can be evaluated, and quality of the channel in a long time cannot be ensured, and therefore, complicated and ever-changing channel fading in the personal area network cannot be dealt with; and on the other hand, there is no specific solution for the coordinator to select from the to-be-scanned channels, there is certain blindness, and if a to-be-scanned channel selected by the coordinator is located in a frequency band adjacent to an interfered frequency band, channel scan and detection efficiency is reduced.